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AssigneeMitsubishi Plastics, Inc.
InventorsKyosuke Watanabe, Yasushi Usami, Yutaka Kawai, Masayoshi Tsujii
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It is to provide a porous film which is excellent in gas permeability (air permeability) and moisture permeability (water vapor permeability), and is excellent in anti-leakage properties and anti-bleeding properties against a liquid, hiding properties and masking properties at an adhesion portion, and a process for producing it. A porous film obtained by melting and kneading a resin composition containing a polyolefin resin {component (A)} and a bulking agent {component (B)} as the main components, and a silicone {component (C)}, or a silicone {component (C)} and castor oil {component (D)}, followed by drawing, which shrinks by from 40 to 95% in one direction and expands by from 5 to 40% in a direction transverse thereto, when soaked in a silicone oil of 200 C for 60 seconds, and a process for producing the above porous film, are provided.
A porous film obtained by melting and kneading a resin composition containing a polyolefin resin {component (A)} and a bulking agent {component (B)} as the main components, and a silicone {component (C)}, or a silicone {component (C)} and castor oil {component (D)}, followed by drawing, which shrinks by from 40 to 95% in one direction and expands by from 5 to 40% in a direction transverse thereto, when soaked in a silicone oil of 200° C. for 60 seconds.
A process for producing a porous film, which comprises melting and kneading a resin composition containing a polyolefin resin {component (A)} and a bulking agent {component (B)} as the main components, and a silicone {component (C)}, or a silicone {component (C)} and castor oil {component (D)}, into a film, and drawing the obtained film from 1.2 to 5 times only in a uniaxial direction at a temperature of from 23° C. to the softening temperature of the resin (as measured in accordance with JIS K6760).
Dependencies are inferred from the claim text.